Safety device for elevators



G. P. MCDONNELL.

SAFETY DEvlcE For: ELEvAToRs. APPLICATION FILED MAY 31. i919.

1,408,459. Pawlltd Mar'. 7, 1922.

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hab iiomey- G. P. MCDONNELL.

SAFETY DEVICE FOR ELEVATORS. APPLlcAloN man MAvs. 1919.

1,408,459. muted Mar. 7, 1922.

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fla-Ngoffffeff if m G. P. MCDONNELL.

SAFETY DEVICE FOR ELEVATORS.

APPL |cATl0N FILED MAY31,1919.

1,408,459. Patented Mar; 7,1922.

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IN1/anion PATENT OFFICE.

GEORG-E 1. MCDQNNELL 0F ST. LQUS. TQISSOURI.

SAFETY DEVICE ELEVATORS.

Application 'tiled May 33,.

To all whom if muy concern:

Be it known thatl l, l. NELL, a citizen of the United Sta; America, a resident of the city of St. fiouis, in the State of Missouri. have invent l tain new and useful lmprovements in I Devices for Elevators, of which the lowing' is a full, clear, and enact descr A tion, reference being' had to the accompanying drawings, forming a part of this speciiication.

My invention relates to improvements in safety devices for elevators, one of the objects being to avoid the liability of serious accidents, which have heretofore been caused by the elevator striking' a part of a persons body or other obstructions in the ele trance. Accidents of the hind referred to are sometimes caused by the elevator strihi t, person leaning' from the elevator landinej into the elevator shaft, for the purpose of determining the location of the elevator. ln this event, the person may be struclr either by the bottom of a downwardly moving;` elevator or by the top of the elevator moving' upwardly in the-shaft. Accidents have also resulted from the elevator striking obstrucn tions, such as lumber carelessly placed on the elevator landing so as to project into the elevator entrance. Again, persons attempting' to leave a inwing elevator have been caught between the V[ioor of the rising` elevator and the top of. the doorway in the elcvator shaft, or if the elevator is movin-agdownwardly, a person attempi'iin,eto pass through the entrance may be caught betw en the `Floor of the landing` and the top of the doorway in the elevator. Furthermore, it sometimes happens that a person inside of a moving elevator will l v tion of his arm or foot extended throu doorway in the elevator, so as to st stationary part of the elevator shaft.

My object is to provide a safety device, or devices, whereby accidents from one or all of the above mentioned acts may be avoided. The combination I have shown to illustrate the preferred form of the invention includes a stopping device for the elevator, and automatically operated members controlling said stopping` device. For example, these automatically operated members may include thrust-receiving abutments in the form of vertically movable striking members adapted to eXtend across the elevator entrance. One of these striking members may be (lf t..

Specification of Lette Patented Mar. 7, 1922.

1919. Serial No. 360,960.

ed across the doorway in the elevator another may be carried by the cage arranged above the top thereof, a third f be car ed by the lower portion of the 'c and arranged below the tloor thereof. and a fourth ma;1 be located across the ele# vater entri-luce and movably secured to the elevator shaft. These striking' members are adapted to engage a part of a persons body, or other member, projecting into the elevator entra-nce, so as to transmit movement ,from the elevator to the stopping,` device, thereby auton'iatically stopping` the elevator. Another object is to provide a simple and expensive means for preventing;` the operation of the elevator when any one of the enti ance doors occupies its open position.

lvl-lith the foregoing` and other objects in view, the invention comprisesthe novel con` shaft, aud also showingsafety devices emf 'ng the features of this invention.

ll is a pcrspeftive view of the elevator can-e, illustrating the safety devices ca rri ed th ereby.

` lll is a diagrammatical view of the rally operated devices,

lV is a diagraminatical view of the operatinemeans for the elevator, and the e for stopping the operatingl means so as to stop the elevator. A

fr desi-@natos an elevator cage, and B desttes the vertical shaft in which the cage is mounted. The different floors or elevator landings are designated by the characters l, 2 and 3! l). Y et each of these landings the elevator shaft is provided with an entrance normally closed by doors 4, and the elevator canje has an entrance or doorway 5 ed to register with the doors 4.

A` safety switch S, carried by the elevator, may be utilized to control a stopping device, as I will be hereinafter described. This switch comprises a fixed contact member 6, a movable contact arm 7, and a spring 8 tendingl to retain said arm in engagement l we,

with the contact member 6. This switch` normally occupies the closed position shown. in Figs. II and III, and if it is openetha stop device will become effective, so as to quickly stop the elevator. In an emergency, this is accomplished by moving the contact arm 7 away from the relativelyv stationary conta-Tft 6. Before describing the stopping device under control of the safety switch, I will point out the means whereby said switch is actuated to stop the elevator.

9 designates a thrust receiving abutment, or striking member', in the form of a chai arranged below the front portion of the elevator and having one of its ends secured to a rigid arm, which extends downwardly from the elevator, its opposite end being sccured to a bell crank lever ll which lies below the movable conte-.ct arm 7. If the chain 9 is forced upwardly, relative to the elevator, the bell crank lever will be actuated to lift the contact arm 7 from the contact 6, thereby stopping the elevator. In other words, if the chain t) strikes an obstruction while the elevator is moving downwardly, the safety switch will be automatically operated to stop the elevator.

Another operating means for the safety switch S includes a chain l2 connected to the contact arm 7, and also connected to a vertical post 13 extending from one of the upper corners of the elevator. rIhis chain l2 has a vertical portion which extends from the contact arm te a pulley` f1.4-, and a horizontal portion 12 extending from said pulley to the post I3. The horizontal portion 12 constitutes a thrust receiving abutment, or striking member, and it lies above the front portion of the elevator, where it will engage a projection of any kind extending` into the elevator shaft at a point above the front of the elevator. If this stril-infr mem ber 12 engages an obstruction while the elevator is moving upwardly, motion will be transmitted. through the chain lf3 to the movable contact arm T to oVL n the .safety switch, thereby stoppingthe elevator.

Another means for operating the stopping switch consists of a long horizontal bar l5 arranged across the elevator entrance, and connected to the chain 12 by means of a relatively weak chain i6, said bar being pivoted at l'i' to the elevator. IS designates a combined guide and stop device for the free end of bar l5. This bar l5, like the members 9 and 12, constitutes a thrust receiving abutment, or striking member, and it may be lifted about the axis of its pivot 17 so as to transmit movement to the chain l2, thereby actuating the stopping switch S.

A' safety switch S', corresponding in function to the stopping switch S', is preferably located at the bottom of the elevator shaft. Thisswitch S comprises a stationary contact 6', a movable contact arm ZA and. a

spring 8 normally retaining these contact members in engagement with each other. The switch S may be opened to stop the elevator, as will be hereinafter described. 19 designates a long vertical switch operating member, preferably a chain or cable, located in the elevator shaft and connected at its lower end to the movable contact arm i. The upper end of this vertical operating` member is connected 'to a counterbalance spring 2O supported by a vertically adjustable rod 2l, said rod being threaded to receive a nut 22 which engagles a bracket 23 in the elevator shaft. The spring 20 is placed under tension by the weight of the vertical operating member I9, and since this spr. ig tends to lift the operating member it serves as a counterbalance which enables the vertical operating member to be easily lifted. y

The means for automatically actuating the vertical member I9 preferably c mprises a series of horiaontal bars 24 (F ig. I), each of which is arranged across the upper portion of an entrance to the elevator and pivoted to the elevator shaft at 25. Relatively weak chains 26 connect the free ends of the bars 2l 'to the vertical operating member I9. If one of the bars Q4 is moved upwardly about the axis of its pivot 25, motion will be transmitted to the vertical operating member I9, and thence to the movable contact member 7, so as to open the safety switch S', thereby stopping the elevator. It will be observed that each of the horizontal hars 2l, pivotallj.Y secured to the elevator shaft, constitutes a thrust receiving member, or striking member, adapted to be engaged bj.' a )rejection of any kind extending from the front of the elevator.

mhe liars 241; 2l may also be actuated by the elevator doors to prevent the elevator from starting when a door occupies its open positien. By referring to Fig. I it will be seen that each bar .is notched to provide a cam il?, vhich normally rests upon a roller 28 carried by an elevator door. When a door moved to its open position, roller 2S cooperates with a cam 27 to lift the bar 2l. and motion is then transmitted from the bar 24 to the vertical operating member 19, with the result of opening the safety switch S. llfhen the door is restored to its closed position, the roller 28 will be located under the cam 27 and the switch S will then be closed by the action of its spring S. The elevator can-notI be operated when the switch S occupies its open position, and it will therefore be understood that the bars 24 cooperating with rollers 28 prevent operation of the elevator when one of the doors occupies its open position. I am aware that it is old to accomplish this particular result by the use of individual electric switches for each elevator door,` but by using the combination heretrance 5 in the elevator.

in shown, a single switch may be used for severalelevator doors. and ifthe electrical elements-fail to properly perform their functions, this single switch lcan be easily inspected for the` purpose of locating the defect in the electrical appliances. Furthermore, this simple switch S cooperates with the bars-24 to Astop theelevat'or. as will be hereinafter pointed out.

From the foregoing description, assuming that the switches S andS may be operated to stop the elevator, it will be readily understood that the safety devices herein shown are adapted to prevent accidents in the following manner:

The ro`ler 28, cooperating with cam 27, will ordinarily prevent the elevator from starting when a door occupies its open position, but this particular feature of the device should not beused in thev combination, or ifit siould fail-to .properly perform its function, accidents from a number -of causes may occurat the elevator entrance. A person attemptingto pass through the doorway 5 in the elevator, whilethe elevator is moving downwardly, may. be caught between the top of the doorway 5 and the elevator landing. In `this event, the striking member will beactuated `totransmit movement to the stopping switch S, thereby quickly vstopping the elevator. Under the same conditions, if theelevator is `moving. upwardly, a person may be caught between the floor of the elevator and the top of the doorway in the elevator shaft. One of the bars 24 would then be actuated to open the stopping lswitch S. The bars 24 may also beactuated by a persons arm or foot projecting from the en- 1When the elevator is moving downwardly, a person standing on one of the landingsand leaning into the elevator shaft may be struck by the yswitch operating member' 9. which will result in actuation of the switch S tostop the elevator. Or, if the elevator is moving upwardly, a person leaning into ythe shaft will be struck by the switch operating member 12 at the top of the elevator. These operating members 9 and 12 are also adapted to strike a proection of any ykind..extending into the front of thc shaft.

A means for operating the elevator is illustrated ydiagramm atfically in IV. designates an electric rnotor having a power shaft 31 provided with a worm 32 meshing with ay worinwheel 33 on a drum 34, around which the elevator operating cable 35 is wound. This is intended to illustrate a. conventional means for operating the elevator. A brake drum 36 (Figs. III and IV) is fixed to the operating shaft 31.- Levers 37, mounted on pivots 38, are provided with brake shoes 39 adapted to engage the drum 36. A

solenoid 40 is provided with oppositely disposed cores 41, which are pivoted to the levers 37. Springs 42 are interposed between the ends of the solenoid and spring seats 43 at the upper ends of levers 37. These springs 42, acting upon the levers 37, tend to force the brake shoes into engagement with the brake drum 36. However, the solenoid 40 may be energized to act upon the cores 41. thereby overcoming the force of springs 42 and releasing the brake shoes 39 from the brake drum.

rfhe means fortransinitting electrical energy to the motor 30 (Fig. III) comprises a main line conductor 44, which may lead directly to the motor, and a conductor consisting of sections 45, 451. 45h, and 45C, through which current is conducted `to or from the motor. In the diagram I have shown, the operatorls switch 46 is adapted to connect the conductor 45" to the conductor 45C, and the safety switch S is used to connect the conductor 45""L to the conductor 451. 47 designates a stopping switch which normally connects the conductor 45 to the conductor 451. Branch conductors 48 connect the solenoid 4() to the conductors 44 and 45C. lVhen all of the switches just referred to are closed, current will flow to the motor 3() and also to the solenoid 40. The solenoid will then be energized to release the brake, and the elevator will be drivenby the motor 30. Under normal conditions, the operators switch 46 is actuated to start and stop the elevator.

When the safety switch S is moved to its open position, the flow of current to the motor 30 and solenoid 40 will be discontinued, and the springs 42 will act upon the levers 37 to force the brake shoes 39 into engagement with the brake drum 36. From the foregoing description, it will be apparent that the safety switch S may be opened to quickly stop the elevator. After the elevator has been stopped in this manner, it may in somecases be desirable to quickly place the operating mechanism under the control of the operators switch 46. For example, it may be necessary to move the elevator a slight distance to release a person who had been caught between the elevator and a portion of the shaft. The circuit including the conductors 45a and 45b is therefore provided with branches 50 and 51 adapted to be connected to each other by a normally Aopen auX- iliary starting switch 52. This switch 52 may be closed to render the safety switch S ineffective. If it is desirable to operate the elevator while the safety switch S occupies its open position, the auxiliary switch 52 is closed by hand, and the electric current will then flow through the switch 52, instead of through the switch S.

The devices controlled by the safety switch S include an electromagnet 53, adapted to attract a pivotally mounted holding device 54 having a projection 55, which cooperates with a hook 56 on the switch arm 47. A

lll

spring 57 tends to pull said switch arm 47 to its open position, but the switch is normally retained in its closed position by the action of the magnet-controlled holding device 54:, which cooperates with the hook 56. The magnet 52 is normally energized by current flowing through conductors 58, 59 and 59, the conductors 59 and 59 being normally connected by the safety switch S on the elevator. When this switch S is moved to its open position, the flow of current to the magnet 53 will be discontinued; the holding device 51 will then be freed from the magnet, and the spring 57 will throw the switch 47 to its open position. his will open the circuit leading to the motor 30 and solenoid 40, with the result of stopping the motor and applying the brakes to quickly stop the elevator. After the elevator has been stopped in this manner, it cannot be again started by merely closing the safety switch S. Therefore, if the switch S is opened as the result of an accident, the elevator will be quickly stopped and it will not be accidentally started by breakage of some part of the mechanism permitting the switch S to return to its closed position. To start the elevator it will be necessary to close the switch 47, and to retain said switch in its closed position it will be. necessary to properly engage the hook 56 with the projection 55, while the magnet 53 is energized to retain said projection 55 in interlocking engagement with the hook.

I have previously referred to a relatively weak connection 16 Figs. I andv II) whereby the striking bar 15 is connected to the switch operating chain 12 through which motion is transmitted to the safety switch S. If an excessive movement is imparted to the striking bar 15, the weak connection 16 will be broken, thereby preventing a person from being seriously injured by the force transmitted through the bar 15. If the weak connection 16 is broken, the safety switch S will be restored to its closedposition, but for the reasons just given this will not restore the switch 47 through which current is conducted to the motor 30 and solenoid 40.

I claim.

1. An elevator provided with a stopping device, a safety switch controlling said stopping device to automaticallystop the elevator, ,and operating means for said safety switch comprising a. thrust receiving abutment in the formV of a movable member extending across the elevator entrance so 'as to be engaged and actuated by a projection moving with the elevator', thereby transmitting movement from the elevator to said safety switch, and operating means carried by the elevator door whereby said thrust receiving member is actuated when the door moves to its open position.

2. The combination of an elevator, a shaft provided with elevator entrances at different elevations, each of said entrances being provided with a door, a stopping device whereby the elevator is stopped, a safety switch adapted to control said stopping device, and means whereby movement it transmitted from all of said doors to actuate said safety switch, said means comprising a movable thrust-receiving abutment across each elevator entrance and operatively connected to said safet switch, and means carried by the elevator oors whereby said thrust-receiving abutments are actuated when the doors are opened.

3. In an elevator provided with a stop ping device, a safety switch controlling said stopping device to automatically stop the elevator, an operating means for said safety switch comprising a movable member extending across the elevator entrance and connecting with said safety switch, said movable member being operably engageable by the elevator door.

4. An elevator provided with a stopping device, a safety switch device carried by the elevator and controlling saidr stopping device to automatically stop the elevator, and operating means for said safety switch device comprising elongated vertically movable striking members arranged transversely of the elevator shaft and carried. by the elevator so as to strike an obstruction projecting into the elevator entrance, one of said striking members being arranged across the doorway in the elevator,A another being below the front of the elevator and another being above the front of the elevator, a switch-operating member carried b the elevator to actuate said safety switch evice, and flexible operating connections leading from all of said striking 7members. to vsaid switch operating member to provide for the transmission of movement from said striking members to said safety switch device.

In testimony that I `claim the foregoing I hereunto affix my signature.

GEORGE P. MCDONNELL. 

